/* $NetBSD: lexer.c,v 1.2 2014/12/20 13:15:48 prlw1 Exp $ */ /* * Copyright (C) 2012 by Darren Reed. * * See the IPFILTER.LICENCE file for details on licencing. */ #include #include "ipf.h" #ifdef IPFILTER_SCAN # include "netinet/ip_scan.h" #endif #include #include #ifdef TEST_LEXER # define NO_YACC union { int num; char *str; struct in_addr ipa; i6addr_t ip6; } yylval; #endif #include "lexer.h" #include "y.tab.h" FILE *yyin; #define ishex(c) (ISDIGIT(c) || ((c) >= 'a' && (c) <= 'f') || \ ((c) >= 'A' && (c) <= 'F')) #define TOOLONG -3 extern int string_start; extern int string_end; extern char *string_val; extern int pos; extern int yydebug; char *yystr = NULL; int yytext[YYBUFSIZ+1]; char yychars[YYBUFSIZ+1]; int yylineNum = 1; int yypos = 0; int yylast = -1; int yydictfixed = 0; int yyexpectaddr = 0; int yybreakondot = 0; int yyvarnext = 0; int yytokentype = 0; wordtab_t *yywordtab = NULL; int yysavedepth = 0; wordtab_t *yysavewords[30]; static wordtab_t *yyfindkey __P((char *)); static int yygetc __P((int)); static void yyunputc __P((int)); static int yyswallow __P((int)); static char *yytexttostr __P((int, int)); static void yystrtotext __P((char *)); static char *yytexttochar __P((void)); static int yygetc(docont) int docont; { int c; if (yypos < yylast) { c = yytext[yypos++]; if (c == '\n') yylineNum++; return c; } if (yypos == YYBUFSIZ) return TOOLONG; if (pos >= string_start && pos <= string_end) { c = string_val[pos - string_start]; yypos++; } else { c = fgetc(yyin); if (docont && (c == '\\')) { c = fgetc(yyin); if (c == '\n') { yylineNum++; c = fgetc(yyin); } } } if (c == '\n') yylineNum++; yytext[yypos++] = c; yylast = yypos; yytext[yypos] = '\0'; return c; } static void yyunputc(c) int c; { if (c == '\n') yylineNum--; yytext[--yypos] = c; } static int yyswallow(last) int last; { int c; while (((c = yygetc(0)) > '\0') && (c != last)) ; if (c != EOF) yyunputc(c); if (c == last) return 0; return -1; } static char *yytexttochar() { int i; for (i = 0; i < yypos; i++) yychars[i] = (char)(yytext[i] & 0xff); yychars[i] = '\0'; return yychars; } static void yystrtotext(str) char *str; { int len; char *s; len = strlen(str); if (len > YYBUFSIZ) len = YYBUFSIZ; for (s = str; *s != '\0' && len > 0; s++, len--) yytext[yylast++] = *s; yytext[yylast] = '\0'; } static char *yytexttostr(offset, max) int offset, max; { char *str; int i; if ((yytext[offset] == '\'' || yytext[offset] == '"') && (yytext[offset] == yytext[offset + max - 1])) { offset++; max--; } if (max > yylast) max = yylast; str = malloc(max + 1); if (str != NULL) { for (i = offset; i < max; i++) str[i - offset] = (char)(yytext[i] & 0xff); str[i - offset] = '\0'; } return str; } int yylex() { #ifdef USE_INET6 static int prior = 0; static int priornum = 0; #endif int c, n, isbuilding, rval, lnext, nokey = 0; char *name; int triedv6 = 0; isbuilding = 0; lnext = 0; rval = 0; if (yystr != NULL) { free(yystr); yystr = NULL; } nextchar: c = yygetc(0); if (yydebug > 1) printf("yygetc = (%x) %c [%*.*s]\n", c, c, yypos, yypos, yytexttochar()); switch (c) { case '\n' : lnext = 0; nokey = 0; case '\t' : case '\r' : case ' ' : if (isbuilding == 1) { yyunputc(c); goto done; } if (yylast > yypos) { bcopy(yytext + yypos, yytext, sizeof(yytext[0]) * (yylast - yypos + 1)); } yylast -= yypos; if (yyexpectaddr == 2) yyexpectaddr = 0; yypos = 0; lnext = 0; nokey = 0; goto nextchar; case '\\' : if (lnext == 0) { lnext = 1; if (yylast == yypos) { yylast--; yypos--; } else yypos--; if (yypos == 0) nokey = 1; goto nextchar; } break; } if (lnext == 1) { lnext = 0; if ((isbuilding == 0) && !ISALNUM(c)) { #ifdef USE_INET6 prior = c; #endif return c; } goto nextchar; } switch (c) { case '#' : if (isbuilding == 1) { yyunputc(c); goto done; } yyswallow('\n'); rval = YY_COMMENT; goto done; case '$' : if (isbuilding == 1) { yyunputc(c); goto done; } n = yygetc(0); if (n == '{') { if (yyswallow('}') == -1) { rval = -2; goto done; } (void) yygetc(0); } else { if (!ISALPHA(n)) { yyunputc(n); break; } do { n = yygetc(1); } while (ISALPHA(n) || ISDIGIT(n) || n == '_'); yyunputc(n); } name = yytexttostr(1, yypos); /* skip $ */ if (name != NULL) { string_val = get_variable(name, NULL, yylineNum); free(name); if (string_val != NULL) { name = yytexttostr(yypos, yylast); if (name != NULL) { yypos = 0; yylast = 0; yystrtotext(string_val); yystrtotext(name); free(string_val); free(name); goto nextchar; } free(string_val); } } break; case '\'': case '"' : if (isbuilding == 1) { goto done; } do { n = yygetc(1); if (n == EOF || n == TOOLONG) { rval = -2; goto done; } if (n == '\n') { yyunputc(' '); yypos++; } } while (n != c); rval = YY_STR; goto done; /* NOTREACHED */ case EOF : yylineNum = 1; yypos = 0; yylast = -1; yyexpectaddr = 0; yybreakondot = 0; yyvarnext = 0; yytokentype = 0; if (yydebug) fprintf(stderr, "reset at EOF\n"); #ifdef USE_INET6 prior = 0; #endif return 0; } if (strchr("=,/;{}()@", c) != NULL) { if (isbuilding == 1) { yyunputc(c); goto done; } rval = c; goto done; } else if (c == '.') { if (isbuilding == 0) { rval = c; goto done; } if (yybreakondot != 0) { yyunputc(c); goto done; } } switch (c) { case '-' : n = yygetc(0); if (n == '>') { isbuilding = 1; goto done; } yyunputc(n); if (yyexpectaddr) { if (isbuilding == 1) yyunputc(c); else rval = '-'; goto done; } if (isbuilding == 1) break; rval = '-'; goto done; case '!' : if (isbuilding == 1) { yyunputc(c); goto done; } n = yygetc(0); if (n == '=') { rval = YY_CMP_NE; goto done; } yyunputc(n); rval = '!'; goto done; case '<' : if (yyexpectaddr) break; if (isbuilding == 1) { yyunputc(c); goto done; } n = yygetc(0); if (n == '=') { rval = YY_CMP_LE; goto done; } if (n == '>') { rval = YY_RANGE_OUT; goto done; } yyunputc(n); rval = YY_CMP_LT; goto done; case '>' : if (yyexpectaddr) break; if (isbuilding == 1) { yyunputc(c); goto done; } n = yygetc(0); if (n == '=') { rval = YY_CMP_GE; goto done; } if (n == '<') { rval = YY_RANGE_IN; goto done; } yyunputc(n); rval = YY_CMP_GT; goto done; } /* * Now for the reason this is here...IPv6 address parsing. * The longest string we can expect is of this form: * 0000:0000:0000:0000:0000:0000:000.000.000.000 * not: * 0000:0000:0000:0000:0000:0000:0000:0000 */ #ifdef USE_INET6 if (yyexpectaddr != 0 && isbuilding == 0 && (ishex(c) || isdigit(c) || c == ':')) { char ipv6buf[45 + 1], *s, oc; int start; buildipv6: start = yypos; s = ipv6buf; oc = c; if (prior == YY_NUMBER && c == ':') { sprintf(s, "%d", priornum); s += strlen(s); } /* * Perhaps we should implement stricter controls on what we * swallow up here, but surely it would just be duplicating * the code in inet_pton() anyway. */ do { *s++ = c; c = yygetc(1); } while ((ishex(c) || c == ':' || c == '.') && (s - ipv6buf < 46)); yyunputc(c); *s = '\0'; if (inet_pton(AF_INET6, ipv6buf, &yylval.ip6) == 1) { rval = YY_IPV6; yyexpectaddr = 0; goto done; } yypos = start; c = oc; } #endif if ((c == ':') && (rval != YY_IPV6) && (triedv6 == 0)) { #ifdef USE_INET6 yystr = yytexttostr(0, yypos - 1); if (yystr != NULL) { char *s; for (s = yystr; *s && ishex(*s); s++) ; if (!*s && *yystr) { isbuilding = 0; c = *yystr; free(yystr); triedv6 = 1; yypos = 1; goto buildipv6; } free(yystr); } #endif if (isbuilding == 1) { yyunputc(c); goto done; } rval = ':'; goto done; } if (isbuilding == 0 && c == '0') { n = yygetc(0); if (n == 'x') { do { n = yygetc(1); } while (ishex(n)); yyunputc(n); rval = YY_HEX; goto done; } yyunputc(n); } /* * No negative numbers with leading - sign.. */ if (isbuilding == 0 && ISDIGIT(c)) { do { n = yygetc(1); } while (ISDIGIT(n)); yyunputc(n); rval = YY_NUMBER; goto done; } isbuilding = 1; goto nextchar; done: yystr = yytexttostr(0, yypos); if (yydebug) printf("isbuilding %d yyvarnext %d nokey %d fixed %d addr %d\n", isbuilding, yyvarnext, nokey, yydictfixed, yyexpectaddr); if (isbuilding == 1) { wordtab_t *w; w = NULL; isbuilding = 0; if ((yyvarnext == 0) && (nokey == 0)) { w = yyfindkey(yystr); if (w == NULL && yywordtab != NULL && !yydictfixed) { yyresetdict(); w = yyfindkey(yystr); } } else yyvarnext = 0; if (w != NULL) rval = w->w_value; else rval = YY_STR; } if (rval == YY_STR) { if (yysavedepth > 0 && !yydictfixed) yyresetdict(); if (yyexpectaddr != 0) yyexpectaddr = 0; } yytokentype = rval; if (yydebug) printf("lexed(%s) %d,%d,%d [%d,%d,%d] => %d @%d\n", yystr, isbuilding, yyexpectaddr, yysavedepth, string_start, string_end, pos, rval, yysavedepth); switch (rval) { case YY_NUMBER : sscanf(yystr, "%u", &yylval.num); break; case YY_HEX : sscanf(yystr, "0x%x", (u_int *)&yylval.num); break; case YY_STR : yylval.str = strdup(yystr); break; default : break; } if (yylast > 0) { bcopy(yytext + yypos, yytext, sizeof(yytext[0]) * (yylast - yypos + 1)); yylast -= yypos; yypos = 0; } #ifdef USE_INET6 if (rval == YY_NUMBER) priornum = yylval.num; prior = rval; #endif return rval; } static wordtab_t *yyfindkey(key) char *key; { wordtab_t *w; if (yywordtab == NULL) return NULL; for (w = yywordtab; w->w_word != 0; w++) if (strcasecmp(key, w->w_word) == 0) return w; return NULL; } char *yykeytostr(num) int num; { wordtab_t *w; if (yywordtab == NULL) return ""; for (w = yywordtab; w->w_word; w++) if (w->w_value == num) return w->w_word; return ""; } wordtab_t *yysettab(words) wordtab_t *words; { wordtab_t *save; save = yywordtab; yywordtab = words; return save; } void yyerror(msg) char *msg; { char *txt, letter[2]; int freetxt = 0; if (yytokentype < 256) { letter[0] = yytokentype; letter[1] = '\0'; txt = letter; } else if (yytokentype == YY_STR || yytokentype == YY_HEX || yytokentype == YY_NUMBER) { if (yystr == NULL) { txt = yytexttostr(yypos, YYBUFSIZ); freetxt = 1; } else txt = yystr; } else { txt = yykeytostr(yytokentype); } fprintf(stderr, "%s error at \"%s\", line %d\n", msg, txt, yylineNum); if (freetxt == 1) free(txt); exit(1); } void yysetfixeddict(newdict) wordtab_t *newdict; { if (yydebug) printf("yysetfixeddict(%lx)\n", (u_long)newdict); if (yysavedepth == sizeof(yysavewords)/sizeof(yysavewords[0])) { fprintf(stderr, "%d: at maximum dictionary depth\n", yylineNum); return; } yysavewords[yysavedepth++] = yysettab(newdict); if (yydebug) printf("yysavedepth++ => %d\n", yysavedepth); yydictfixed = 1; } void yysetdict(newdict) wordtab_t *newdict; { if (yydebug) printf("yysetdict(%lx)\n", (u_long)newdict); if (yysavedepth == sizeof(yysavewords)/sizeof(yysavewords[0])) { fprintf(stderr, "%d: at maximum dictionary depth\n", yylineNum); return; } yysavewords[yysavedepth++] = yysettab(newdict); if (yydebug) printf("yysavedepth++ => %d\n", yysavedepth); } void yyresetdict() { if (yydebug) printf("yyresetdict(%d)\n", yysavedepth); if (yysavedepth > 0) { yysettab(yysavewords[--yysavedepth]); if (yydebug) printf("yysavedepth-- => %d\n", yysavedepth); } yydictfixed = 0; } #ifdef TEST_LEXER int main(argc, argv) int argc; char *argv[]; { int n; yyin = stdin; while ((n = yylex()) != 0) printf("%d.n = %d [%s] %d %d\n", yylineNum, n, yystr, yypos, yylast); } #endif